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* [PATCH] clocksource: armada-370-xp: Register sched_clock after the counter reset
@ 2013-11-26 21:20 Ezequiel Garcia
  2013-11-26 21:40 ` Jason Cooper
  2013-11-28  8:24 ` Daniel Lezcano
  0 siblings, 2 replies; 3+ messages in thread
From: Ezequiel Garcia @ 2013-11-26 21:20 UTC (permalink / raw)
  To: linux-arm-kernel

This commit registers the sched_clock _after_ the counter reset
(instead of before). This removes the timestamp 'jump' in kernel
log messages.

Before this change:

[    0.000000] sched_clock: 32 bits at 25MHz, resolution 40ns, wraps every 171798691800ns
[    0.000000] Initializing Coherency fabric
[    0.000000] Aurora cache controller enabled
[    0.000000] l2x0: 16 ways, CACHE_ID 0x00000100, AUX_CTRL 0x1a696b12, Cache size: 1024 kB
[  163.507447] Calibrating delay loop... 1325.05 BogoMIPS (lpj=662528)
[  163.521419] pid_max: default: 32768 minimum: 301
[  163.526185] Mount-cache hash table entries: 512
[  163.531095] CPU: Testing write buffer coherency: ok

After this change:

[    0.000000] sched_clock: 32 bits at 25MHz, resolution 40ns, wraps every 171798691800ns
[    0.000000] Initializing Coherency fabric
[    0.000000] Aurora cache controller enabled
[    0.000000] l2x0: 16 ways, CACHE_ID 0x00000100, AUX_CTRL 0x1a696b12, Cache size: 1024 kB
[    0.016849] Calibrating delay loop... 1325.05 BogoMIPS (lpj=662528)
[    0.030820] pid_max: default: 32768 minimum: 301
[    0.035588] Mount-cache hash table entries: 512
[    0.040500] CPU: Testing write buffer coherency: ok

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
---
Nobody has ever complained about the 'jump' in the timestamp, so maybe
this is a stupid and useless change.

 drivers/clocksource/time-armada-370-xp.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/clocksource/time-armada-370-xp.c b/drivers/clocksource/time-armada-370-xp.c
index d8e47e5..4e7f680 100644
--- a/drivers/clocksource/time-armada-370-xp.c
+++ b/drivers/clocksource/time-armada-370-xp.c
@@ -256,11 +256,6 @@ static void __init armada_370_xp_timer_common_init(struct device_node *np)
 	ticks_per_jiffy = (timer_clk + HZ / 2) / HZ;
 
 	/*
-	 * Set scale and timer for sched_clock.
-	 */
-	sched_clock_register(armada_370_xp_read_sched_clock, 32, timer_clk);
-
-	/*
 	 * Setup free-running clocksource timer (interrupts
 	 * disabled).
 	 */
@@ -270,6 +265,11 @@ static void __init armada_370_xp_timer_common_init(struct device_node *np)
 	timer_ctrl_clrset(0, TIMER0_EN | TIMER0_RELOAD_EN |
 			     TIMER0_DIV(TIMER_DIVIDER_SHIFT));
 
+	/*
+	 * Set scale and timer for sched_clock.
+	 */
+	sched_clock_register(armada_370_xp_read_sched_clock, 32, timer_clk);
+
 	clocksource_mmio_init(timer_base + TIMER0_VAL_OFF,
 			      "armada_370_xp_clocksource",
 			      timer_clk, 300, 32, clocksource_mmio_readl_down);
-- 
1.8.1.5

^ permalink raw reply related	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2013-11-28  8:24 UTC | newest]

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2013-11-26 21:20 [PATCH] clocksource: armada-370-xp: Register sched_clock after the counter reset Ezequiel Garcia
2013-11-26 21:40 ` Jason Cooper
2013-11-28  8:24 ` Daniel Lezcano

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